Self-Cooling Package

ABSTRACT

A self-cooling package comprises a first cavity ( 10 ) containing a product to be cooled, a second cavity ( 20 ) forming a heat exchanger and containing a coolant liquid suitable for evaporating under the effect of a depression and a third cavity ( 30 ) containing an adsorbent ( 31 ) suitable for trapping the coolant liquid vapours. The package also comprises a container ( 40 ) suitable for receiving at least the third cavity ( 30 ), at least a part of the walls ( 41 ) of the container ( 40 ) having a thickness of less than 0.15 mm. The package uses a container having a thin wall thickness to receive the adsorbent, which is inexpensive and easy to manufacture. The manufacture of the package is thus simplified and reduced. The container wall thinness also ensures limited heat leakage towards to cooled product.

The present invention relates to a package making it possible to cool down its content by an evaporation and adsorption method. The invention is used for cooling food products such as beverages, ice creams, and also non-food products such as pharmaceutical or cosmetic products.

The implementation of the method of cooling by evaporation and adsorption is known and has been the subject of numerous research projects in the prior art. The principle of such a cooling method involves evaporating a liquid, a so-called coolant liquid, under the effect of a low pressure maintained by pumping said liquid vapours. The pumping may be ensured by an adsorbent, generally desiccants, suitable for trapping the coolant liquid vapours. Numerous devices have been proposed, combining a heat exchanger containing a liquid to be evaporated with a reservoir containing an adsorbent, in particular for uses for self-cooling beverage packages.

The document WO 01/11297 describes a self-cooling beverage package comprising a heat exchanger immersed in a beverage can assembled by a panel to a container containing an adsorbent comprising desiccants in the form of granules. The connection between the heat exchanger and the desiccant container is activated by a cutter in order to allow the implementation of the cooling by evaporation and adsorption of the coolant liquid vapours contained in the exchanger.

This document describes the manufacturing process for such a self-cooling beverage package and in particular the stages of assembling the different elements constituting the package. The desiccant reservoir used in this document is a triple container with a thickness of 0.16 mm drawn in order to make it possible to house heat traps in the fingers formed by drawing. The assembly (desiccant container and heat traps) is then placed in a container of cylindrical format assembled with the beverage can.

Such a package has certain drawbacks. In particular, the container containing the adsorbent is not optimized. In fact, the desiccant reservoir is a part designed specifically for this package requiring a particular drawing manufacturing operation. The reservoir then has to be assembled with the heat traps in the container. Thus, the container containing the adsorbent requires a set of complex and expensive manufacturing stages.

Moreover, the stage of assembling the container containing the desiccants with the can containing the heat exchanger is particularly delicate as it is essential to maintain a high vacuum in the desiccant reservoir and in the vicinity of the cutting seal in order to guarantee the effectiveness of the evaporation and adsorption reaction.

The need to maintain a high vacuum in the desiccant reservoir imposes significant constraints on the reservoir, in particular with regard to the choice of its shape and thickness of its walls, in order to avoid crushing the container under the effect of the external atmospheric pressure.

Moreover, good management of the flow of heat between the cooled product and the adsorbent which is heated during the cooling reaction is necessary. In particular, it is necessary so far as possible to limit the conduction of heat released by the adsorbent towards the cooled product.

A need therefore exists for a simplified self-cooling package, in particular for a simplified adsorbent container, with a reduced thermal bridge between the adsorbent and the cooled product.

To this end, the present invention proposes arranging the adsorbent in a container having a thin wall thickness in order to limit heat conduction. The invention thus proposes using a container which is available in large quantities, inexpensive and simple in shape. In particular, the present invention aims to use cans, of the standard beverage can type, to contain the adsorbent. Such containers are available in large quantities on the market at a moderate price.

The invention more particularly relates to a self-cooling package comprising:

-   -   a first cavity containing a product to be cooled;     -   a second cavity forming a heat exchanger and containing a         coolant liquid suitable for evaporating under the effect of a         depression;     -   a third cavity containing an adsorbent suitable for trapping the         coolant liquid vapours;     -   a container suitable for receiving at least the third cavity, at         least a part of the walls of the container having a thickness of         less than 0.15 mm.

According to the embodiments, the self-cooling package according to the invention may comprise one or more of the following features:

-   -   at least a part of the walls of the container has a thickness         comprised between 0.08 and 0.1 mm;     -   the container has beadings;     -   the adsorbent is moulded into a rigid block so as to ensure         maintenance of the walls of the container;     -   the beadings are formed in a portion of the side walls extending         beyond the adsorbent block;     -   the container also contains at least a part of the second         cavity;     -   the container also contains at least a part of the first cavity;     -   the container is cylindrical;     -   the container is constituted by a can or a portion of a can;     -   the container is made of steel;     -   the second cavity has a common wall with the third cavity, the         edges of said common wall being fixed to the container;     -   the second cavity has a common wall with the first cavity, the         edges of said common wall being fixed to the container;     -   the first cavity is separated from the adsorbent by an extension         of the side walls of the container beyond the adsorbent;     -   the second cavity is separated from the adsorbent by an         extension of the side walls of the container beyond the         adsorbent.

The invention also covers the use of such a self-cooling package for a cosmetic product contained in the first cavity of the package and/or for an iced product contained in the first cavity of the package.

The features and advantages of the present invention will become apparent during the description which follows, given by way of illustrative and non-limitative example, and made with reference to the figures which represent:

FIG. 1, a diagram of a self-cooling package according to a first embodiment of the invention;

FIG. 2, a diagram of a self-cooling package according to a second embodiment of the invention;

FIG. 3, a diagram of a self-cooling package according to a third embodiment of the invention.

The self-cooling package according to the invention comprises a first cavity containing a product to be cooled, a second cavity forming a heat exchanger and a third cavity containing an adsorbent. The heat exchanger contains a coolant liquid suitable for being evaporated under the effect of low pressure and the adsorbent is suitable for trapping the coolant liquid vapours. The package also comprises a container suitable for receiving at least the third cavity, at least a part of the walls of the container having a thickness of less than 0.15 mm.

The package according to the invention uses a container which is not very thick, and which is inexpensive and easy to manufacture, to contain the adsorbent. The manufacture of the package is thus simplified and its cost reduced.

The thinness of the wall of the adsorbent container also makes it possible to reduce the thermal bridge towards the cooled product by limiting heat leaks along the walls of the container.

The package will be described more precisely with reference to the figures.

The self-cooling package according to the invention comprises a first cavity 10 containing a consumer product to be cooled, such as a beverage, an ice cream or a cosmetic cream to be applied.

The package also comprises a second cavity 20 forming a heat exchanger and containing a coolant liquid the evaporation of which produces the cooling. The second cavity 20 contains the coolant liquid and its vapours. The pressure in the second cavity before the start of the evaporation reaction is approximately 30 mbar at 23° C. The first 10 and the second 20 cavities have a common wall 15 which constitutes a heat exchanger. The cold created in the second cavity 20 by the evaporation of the coolant liquid may be transmitted to the product contained in the first cavity 10 via this common wall 15.

The package also comprises a third cavity 30 containing means of pumping by adsorption the vapours of the coolant liquid from the second cavity 20. The third cavity, under air vacuum, contains an adsorbent 31 placed in a container 40. This container 40 therefore receives at least the third cavity 30 of the package.

The container 40 has a base 42 and side walls 41. The container 40 illustrated in the figures is cylindrical in form. At least a part of the walls 41 of the container 40 has a thickness of less than 0.15 mm. In particular, at least a part of the walls of the container may have a thickness comprised between 0.08 and 0.1 mm. For example, a can or a portion of a can, of the standard beverage can type, may be used as the container 40.

Standard cans may be made out of steel or aluminium. The side walls generally have a thickness of approximately 0.08 mm with a thickness of approximately 0.12 mm at the top and bottom part. The base of the can generally has a thickness of approximately 0.23 mm. Such a standard can cannot however support an internal high vacuum without being crushed under the effect of atmospheric pressure. In fact, a can only has good mechanical resistance when it is subjected to overpressure on the inside. Such overpressure is generally provided by the beverage contained in the can, the latter being able to be crushed manually without effort once the beverage has been consumed.

In order to guarantee good effectiveness of pumping by the adsorbent, it is necessary for the third cavity 30 to be assembled and closed under vacuum, with a vacuum of less than 1 mbar and preferably of less than 0.1 mbar. Indeed, the cooling reaction is initiated by a low pressure when the heat exchanger (the second cavity) is connected to a zone of stronger low pressure (the third cavity). This cooling reaction is then maintained by pumping the coolant liquid vapours by the adsorbent, from the second cavity 20 towards the third cavity 30.

According to an embodiment, the adsorbent is moulded into a rigid block. Such a block may be moulded with cavities constituting conduits for supplying the adsorbent with the coolant liquid vapour. For example, a zeolite powder may be mixed with a binder and water in order to form a thick paste which it is possible to shape into a block provided with cavities. The shaping of the adsorbent block with its cavities may be carried out by injection moulding and pressing or by extrusion for example. The moulding of the adsorbent into a rigid block is described in the applicant's Patent Application EP-A-1 297287. The adsorbent thus moulded ensures the maintenance of the walls of the container at external atmospheric pressure. Such a moulding of the adsorbent does not at all detract from its adsorption capacities, in particular thanks to the cavities formed in the block, and makes it possible to ensure maintenance of the walls of the container 40. Indeed, the force exerted by the external atmospheric pressure on the walls of the container 40 is compensated for by a reaction force provided by the adsorbent block which may support the walls.

According to another embodiment, beadings 43 are formed in the side walls 41 of the container 40. By beadings is meant a structuring of the wall giving it an increased apparent thickness. The structuring may consist of corrugations for example. The beadings 43 make it possible to reinforce the vacuum resistance of the side walls of the container 40 when the adsorbent arranged in the third cavity is not rigid, for example in the form of granules.

Means for starting the cooling reaction are provided. The cooling reaction is started by connecting the second 20 and third 30 cavities. The starting means may comprise a check valve 44 blocking an opening in a common wall 25 of the second and third cavities. This valve 44 has the feature of only being able to open towards the outside of the third cavity 30 by the action of a force exerted on the side of the third cavity 30. The check valve 44 may be actuated by a push rod 45 transmitting a displacement of at least a portion of the base 42 of the container 40, this base being opposite the wall 25 comprising the connecting means. Such starting means are described in the applicant's Patent Application WO 03/073019.

Such starting means may easily be actuated due to the fact that the third cavity 30 is under an air vacuum. A weak pressure exerted on the base 42 of the container 40 may therefore easily lead to a deformation towards the inside, in particular if the base is structured as a convex dome.

Thus, it is possible to use a simple, inexpensive container which is available in large quantities, in order to produce at least a part of the self-cooling package according to the invention.

Apart from the cost reduction, the use of a container having a small thickness, such as a standard can or a portion of a can, makes it possible to limit heat leaks from the adsorbent towards the cooled product.

In fact, the quantity of heat conducted by a material depends on its thermal conductivity and its section. A steel rather than an aluminium container will preferably be chosen, steel having a thermal conductivity four to five times less than that of aluminium. According to an embodiment, the side walls 41 of the container 40 may extend beyond the adsorbent block 31. The container 40 may then contain, in addition to the third cavity 30, at least a part of the second cavity 20 and also at least a part of the first cavity 10.

The use of a container 40 with side walls with a thickness of less than 0.15 mm makes it possible to limit the transfer of heat from the third cavity 30 towards the first 10 and second 20 cavities via the side walls 41.

Moreover, the package according to the invention has easy assembly features. Several methods of assembly will be described by way of example.

According to a first embodiment, illustrated in FIG. 1, the container 40 contains a large part of the first cavity 10 and all of the second 20 and third 30 cavities. The cavities 10, 20, 30 of the package constitute compartments of a single container 40, for example a portion of a can, of standard beverage can type. A separation cover 25 between the second 20 and third 30 cavities is introduced into the container 40 and fixed by gluing or bracing against the internal walls of the container 40. A cup 15 serving as a receptacle for the product to be cooled constitutes the common wall of the first 10 and second 20 cavities. This cup 15, forming the heat exchanger, is introduced into the container and fixed by crimping onto the edge of the side walls 41 of the container 40, after the coolant liquid has been introduced into the second cavity 20. The cup 15 could just as well be fixed by gluing or bracing against the walls 41 of the container 40.

The cup 15 may contain for example a cosmetic cream to be cooled before application. It cooperates with a lid 5 which may be clipped for example. The first cavity 10 containing the product to be cooled may be separated from the adsorbent block so as to reduce the thermal bridge between the adsorbent and the cooled product. Similarly, the second cavity 20 forming the heat exchanger may be separated from the adsorbent block 31. In fact, during the cooling reaction, the adsorbent 31 is heated and it is desirable to prevent a flow of heat from rising towards the heat exchanger and the cooled product. The heat leak along the side walls 41 of the container as far as the heat exchanger generates additional cooling by additional evaporation which causes additional adsorption. When the quantity of adsorbent used is limited, this additional adsorption becomes difficult to manage.

A separation of the first and second cavities from the adsorbent block 31 is therefore ensured by an extension of the side walls 41 of the container 40 beyond the adsorbent block. Notably, the side walls 41 of the container 40 may extend along the third cavity 30 beyond the adsorbent block 31. The heat leaks along the walls 41 of the container 40 may then be released to the maximum extent towards the outside atmosphere before reaching the first and second cavities.

Beadings 43 are then formed in the portion of side walls 41 extending beyond the adsorbent block 31. Beadings may also be formed on other portions of the container 40. The beadings in particular make possible an improved vacuum resistance on the container portion receiving the second and third cavities beyond the adsorbent block.

According to a second embodiment, illustrated in FIG. 2, the container 40 contains a small part of the first cavity 10 and the whole of the second 20 and third 30 cavities. The package is then constituted by the container 40, for example a portion of a can, and another container 50 mounted by gluing or bracing onto the end of the walls of the container 40. The container 50 serves as a receptacle for the product to be cooled, for example an ice cream. It cooperates with a lid 55 which may be screwed on for example.

The first cavity 10 is also separated from the adsorbent block 31 in order to reduce the thermal bridge. This limitation of the thermal bridge is important when it is desired to cool the product in the first cavity below 0° C. while using a limited quantity of adsorbent. Good management of the heat flows rising towards the heat exchanger and the cooled product is then necessary. The distancing of the first cavity from the adsorbent block is here also ensured by an extension of the side walls 41 of the container 40 beyond the adsorbent block along the third cavity 30. Beadings 43 are then formed in the portion of side walls 41 extending beyond the adsorbent block 31.

According to a third embodiment, illustrated in FIG. 3, the container 40 contains the whole of the first 10, second 20 and third 30 cavities. The cavities 10, 20, 30 of the package then constitute compartments of a single container 40, for example a can of the standard beverage can type. A separation cover 25 between the second 20 and third 30 cavities is introduced into the container 40 and fixed by gluing or bracing onto the inside walls of the container 40. The common wall 15 of the first 10 and second 20 cavities, forming the heat exchanger, is also introduced into the container 40 and fixed by gluing or bracing, after the coolant liquid has been introduced. The heat exchanger 15 has a conical shape, optionally with ribs, in order to promote the exchange of heat by convection in the first cavity 10 when the latter contains a beverage to be cooled.

According to this embodiment, the first cavity 10 containing the beverage to be cooled is not separated from the adsorbent block 31. In fact, the quantity of adsorbent 31 used being five to eight times greater in this embodiment, the additional adsorption generated by the heat leak along the walls 41 of the container 40 may be ensured by means of a greater heat leak towards the outside atmosphere. Such a management of the heat flows is described in the applicant's Application WO 03/059779. Moreover, the transfer of heat from the adsorbent block towards the first cavity remains limited by the thinness of the wall of the container.

The adsorbent block 31 may then almost completely fill the third cavity 30. The beadings are then not necessary.

According to the invention, a simplified self-cooling package may be manufactured.

Of course, the present invention is not limited to the embodiments described by way of examples; thus, the assembly of the cavities constituting the package may adapt to the applications envisaged, in particular, the shapes and dimensions may vary, as well as the arrangement of the cavities in the container. The examples illustrated show the adsorbent moulded as a rigid block, but it is understood that the package according to the invention may use an adsorbent in the form of granules for example. Similarly, the use of a can or a portion of a can as a container 40 has been mentioned, but any container having walls with a thickness of less than 0.15 mm may be used within the scope of the invention. 

1: Self-cooling package comprising: a first cavity containing a product to be cooled; a second cavity forming a heat exchanger and containing a coolant liquid suitable for evaporating under the effect of a depression; a third cavity containing an adsorbent suitable for trapping the coolant liquid vapours; a container (suitable for receiving at least the third cavity, at least a part of the walls of the container having a thickness of less than 0.15 mm. 2: Self-cooling package according to claim 1, wherein at least a part of the walls of the container has a thickness comprised between 0.08 and 0.1 mm. 3: Self-cooling package according to claim 1, wherein the container has beadings. 4: Self-cooling package according to claim 1, wherein the adsorbent is moulded into a rigid block so as to ensure maintenance of the walls of the container. 5: Self-cooling package according to claim 4, wherein the container has beadings that are formed in a portion of side walls extending beyond the adsorbent block. 6: Self-cooling package according to claim 1, wherein the container also contains at least a part of the second cavity. 7: Self-cooling package according to claim 1, wherein the container also contains at least a part of the first cavity. 8: Self-cooling package according to claim 1, wherein the container is cylindrical. 9: Self-cooling package according to claim 1, wherein the container is constituted by a can or a portion of a can. 10: Self-cooling package according to claim 1, wherein the container His made of steel.
 11. Self-cooling package according to claim 1 wherein the second cavity has a common wall with the third cavity, the edges of said common wall being fixed to the containers. 12: Self-cooling package according to claim 1, wherein the second cavity has a common wall with the first cavity, the edges of said common wall being fixed to the containers. 13: Self-cooling package according to claim 1, wherein the first cavity is separated from the adsorbent by an extension of the side walls of the container beyond the adsorbent. 14: Self-cooling package according to claim 1, wherein the second cavity is separated from the adsorbent by an extension of the side walls of the container (beyond the adsorbent. 15: Use of a self-cooling package according to claim 13 for a cosmetic product contained in the first cavity of the package. 16: Use of a self-cooling package according to claim 13 for an iced product contained in the first cavity of the package. 17: Self-cooling package according to claim 3, wherein the container also contains at least a part of the second cavity. 18: Self-cooling package according to claim 3, wherein the container also contains at least a part of the first cavity. 19: Self-cooling package according to claim 13, wherein the container has beadings that are formed in a portion of side walls extending beyond the adsorbent. 20: Self-cooling package according to claim 2, wherein the container has beadings. 21: Self-cooling package according to claim 2, wherein the adsorbent is moulded into a rigid block so as to ensure maintenance of the walls of the container. 22: Use of a self-cooling package according to claim 14, for a cosmetic product contained in the first cavity of the package. 23: Use of a self-cooling package according to claim 14, for an iced product contained in the first cavity of the package. 24: Self-cooling package according to claim 14, wherein the container has beadings that are formed in a portion of side walls extending beyond the adsorbent. 